Well. What is on the floor, what is in the shower, is there a tub, how far beyond a vanity in reno, is the bath going?

Personally........I'd LOSE the niche entirely, and free myself.

Show the rest of the bath, and inform as to your plans.....none of this as seen, suggests blue. Any shade.

You keep seeing things...in isolation. Cut that out : )

Nothing lives in isolation . Not that niche, especially.

I think the niche stone is beautiful and should stand alone by using rectangle bevel edge mirrors. Gold light, pointed down easier to clean. Will be beautiful!

The niche is all warm colors, but the white, navy and gray are all cool colors, so they don't go together. If the tile in the shower and on the floor is the same tones as the niche, you need to look to warm colors for your vanity. A creamy white instead of a white-white would work, or natural wood. There are hundreds of paint colors, so choose your vanity and top first before you look at paint colors. But again, a bright white will not work. Can you show us the floor and shower so we can see everything you're working with?

@JAN MOYER @kandrewspa Good questions, information I should have provided! We will be carrying over medium brown LVP from the master bedroom (which I know is controversial)! We are deciding between https://shawfloors.com/flooring/vinyl/details/praxis-plank-3039v/chaucer OR https://www.happyfeetinternational.com/products/mustang (Autumn).

We will be replacing the shower (making it bigger by knocking out the little wall by the tub and will be frameless). I was thinking whatever material we choose for the vanity countertop, I could use larger tiles/slabs of that for the shower. We do have white subway tile in the kitchen but not sure if it would make sense to do that in shower too.

We will replacing the tub with a freestanding tub and faucet (maybe one of these? https://www.lowes.com/pl/Freestanding--Bathtubs-Bathtubs-whirlpool-tubs-Bathroom/4294737274?searchTerm=freestanding%20tub&sortMethod=sortBy_priceLowToHigh&refinement=1040479095,4294419285&view=List ) I was thinking of removing the shutters from the window too.

It's hard because so much of this is unknown/a blank slate! lol

You need to hold your horses. Draw the bath to scale. All of it, as the original condition. Measure every wall, doorway window ..everything, to the inch.

Your intrepid design method? Not good. Out of order, and can lead to small or large disaster in both looks and function. Such as.....I doubt very much you have enough room for a free standing tub.

You have a lot of areas going. You need a designer. that is the best advice you will get. Local to you and your SITE.

what jan said.

however, if you want to do freestanding, you'll end up w/something like these

the pic above is the before but they are redoing it for a larger shower w/bench. this is what it looks like in iprogress. this will be a small tub.

So when planning your space, figure out what you want and measure.

yes remove the shutters. do a nice blind or get obscure glass. (or, since you're up so high, do you really need window coverings??)

as for the vanity area, is that niche going to go w/whatever tile element you're choosing? like, italian/tuscan? the transitional white vanity won't work w/that niche style.

see?

if you like it, take it out, square it up, put some wood shelves in it w/diff mosaic tile.

do square top mirrors and a nice light. you can also do a ceiling light.

start looking at bathroom pics to see what design you like.

Like Jan and Beth said, you putting the cart before the horse.

New home - live there for 6 months to a year before doing any major renovations.

During that time prioritize your needs, wants and like to have renovations and figure out the budget for renovations. Every renovation you commit to will take twice as long as you think it will and cost twice as much as you think it will.

Budget should be dependent at least in part to the amount of time you believe you will live in the home.

You should also be exploring your style and color selections.

Once you have a solid budget you will know what things must stay and what you can afford to change and what elements you don't want to change.

Once you know what has to stay you can design around those elements. Do they work with your preferred style and colors? What compromises will you need to make to create a cohesive home?

I am not a contractor, but if you are planning on expanding the shower I am pretty sure the old shower has to be re-tiled. The whole shower has to be water sealed and that seal is under the tile. I don't think you can save the tile in the niche.